JP2010500924A5 - - Google Patents

Description

Control of welding equipment

  The present invention relates to a driving method and a driving apparatus for a welding apparatus, particularly an electric resistance pressure welding apparatus.

  Various welding devices and welding methods are known from the prior art. In particular, electronic welding equipment is mainly used in the automotive industry. Such an electronic welding apparatus has two welding electrodes. A welding current flows between these welding electrodes. This welding current is used to weld the workpiece to be processed. Here, this welding current is normally supplied from a converter. In this case, currents up to 20 kA are usually used for welding in the case of welding voltages in the region of 1 to 2.5V. Larger currents are also used depending on the material of the welding task. The individual welding processes here take place within a time window in the region of up to 1 second. But longer times are possible.

  In the prior art, a constant welding current has been used for the welding process so far. However, in many cases it is effective to change the welding current in order to perform the welding process optimally over its entirety or over time. Correspondingly, it is known from the prior art to adjust the welding current and another characteristic amount of the welding process via the adjusting part. Such adjustments now have access to a reference curve specific to the corresponding welding process. So far, the reference curves required by the adaptive adjuster for the adjustment and monitoring operations have been loaded into the adjustment module as individual curves. These reference curves are recorded via a reference welding process that takes place before the original operating process.

  However, this creates a risk that the non-optimal reference curve is stored in the adjustment module as a basis for adjustment, and the adjustment unit does not operate optimally on this basis. The causes of such non-optimal curves are, for example, splash welding, very worn electrode caps, freshly milled electrode caps and another amount of noise.

  Thus, in the methods known from the prior art, the reference curve depends on the current system condition (eg electrode cap wear condition) or whether an optimal reference curve is created depends on the current system condition. To do.

  For example, if process quantities such as cooling and force of welding forceps are not stable at the time of reference welding, such an incomplete state is also learned as a reference.

  In such a case, the adjustment unit refers to an incorrect standard and cannot operate optimally.

  Furthermore, in many types of thin plates, for example, a fluctuation zone having a large resistance curve occurs. Such a variation cannot be dealt with by a curve used as a reference curve. In other words, it is not possible to determine a stable process zone for which a suitable reference curve should exist. This is because there is a lack of comparison to other curves.

  Accordingly, it is an object of the present invention to provide a method and welding apparatus that allows improved alignment to different system conditions. In particular, a method should be provided that allows improved matching of the coordinator. In addition, a method should be provided that allows monitoring of the welding process.

  The above problems are solved according to the invention by the method of claim 1 and the welding apparatus of claim 11. Advantageous embodiments and developments are described in the dependent claims.

  In the welding device operating method according to the invention, the welding device has at least one welding electrode, preferably two welding electrodes. This is driven by a current with at least one variable electrical reference quantity, where this electrical reference quantity is controlled by a control device, the control of the electrical reference quantity being specific to the welding process to be performed. This is done taking into account the reference data set. In the present invention, the reference data set is determined based on at least one raw data set. This raw data set is here specific to the welding process to be performed.

In particular, the electrical reference quantity is a parameter or quantity characterizing the current. Advantageously, the electrical reference quantity is selected from a group of reference quantities. This reference quantity group includes welding current, welding voltage, output, energy, rise phase , combinations thereof, and the like, and particularly includes welding current.

  The invention further relates to a method for controlling and / or monitoring a welding apparatus. The welding device here has at least one welding electrode. The welding electrode is driven by at least one electrical reference quantity, which is controlled by a control device. Here, the control of the electrical reference amount is performed in consideration of a reference data set specific to the welding process to be performed. In the present invention, the reference data set is compared with at least one raw data set that characterizes the measurement process to be performed, and this comparison provides information about the welding process to be performed.

  This comparison of the reference data set and the raw data set provides information on whether the welding was performed correctly. For example, if the raw data set deviates significantly from the reference data set, it can be inferred that the weld has an error accordingly. In this way, the welding process is monitored. In this way, raw data sets are created in two inventive methods, which are used for monitoring and control of the welding apparatus.

  Advantageously, the fluctuation band is defined around the reference data set. If the raw data set is within this fluctuation range, a correspondingly performed weld is considered to be acceptable. If the determined raw data set is (partially) outside this band, the welding process is no longer correct.

  The electrical reference quantity is preferably adjusted by an adjusting device. However, note that: That is, it should be noted that the method of the present invention is used not only for adjusting the reference amount but also for monitoring the welding process.

  The reference data set is preferably determined from a number of raw data sets. Here, each raw data set is specific to the welding process to be performed. However, this method does not specifically handle only averaging over individual raw data sets.

  The reference data set is also referred to below as the reference curve. This reference curve indicates a specific welding process and includes, for example, a data pair such as a characteristic value with respect to the welding current, depending on the time of measurement.

  Thus, in the context of this specification, the data set specific to the welding process to be performed is in particular a data set recorded for the same or similar welding process. Thus, a particular data set is specific to a welding process performed with a particular welding electrode, with a particular material to be welded, or with a similar material.

  By using multiple raw data sets that are specific to the welding process to be performed in the same way, it is possible to create a reference data set that suppresses possible outliers due to erroneous measurements . Furthermore, in this way, an averaged reference data set is obtained that accurately represents the welding process to be performed.

  In other words, the unexpected factors described above can be dealt with, for example, by expanding the corresponding operation surface of the welding apparatus.

  Specifically, during manufacturing, the weld is automatically recorded for each program or each welding point for a predetermined time in response to a new function call according to the invention, for example stored in a PC or a welding control. Is done. In other words, a number of welding processes are recorded, which later provides improved information in the reference data set.

  After such recording is completed, the user is provided with a group of curves (eg, multiple resistance courses) for each welded program or each welding point (individual controls and devices for each program). Is networked). Based on such a group of curves, the user can identify outliers, such as splash welds or obstructed welds, which can be deleted, for example by clicking a mouse. However, such identification or deletion may be performed automatically.

  Furthermore, the user can identify stable process zones and better estimate the position of the reference curve to be created.

  After removing the abnormal values described above, the group of curves is then averaged and stored as a reference data set in the adjustment module of the welding controller.

In this way, it is ensured that the reference data set is located at the center of the process band described above or at a position generally defined by the user. Advantageously, in determining the group of curves described above, all the quantities measured or derived are averaged. This is for example current, voltage, rising phase , resistance, output and energy.

  In an advantageous manner, the reference data set includes a number of value pairs, for example time values, for which resistance values are indicated.

  The reference data set is preferably created by using mathematical operations on at least one raw data set and particularly preferably at least one raw data set part. This calculation is averaging or the like. In particular, the mathematical operation is selected from a mechanical operation group. This group of operations includes average value calculation, especially arithmetic average value calculation or geometric average value calculation, integral formation, total value formation, and combinations thereof. Arithmetic averaging is preferably used, whereby the individual raw data sets are averaged, thus creating a reference data set. However, when arithmetic operations are used only on the raw data set, such smoothing of the raw data set is not limited.

In another advantageous manner, each value pair includes a first value and at least one second value assigned to the first value. However, it is also possible to assign a plurality of second values to one first value. This is, for example, a current value, a voltage value, a resistance value derived therefrom , a value for the rising phase and a value for the output and energy. In this case, this is not a value pair, but n sets (n-Tupel).

  Advantageously, mathematical operations are used on the second values of the various raw data sets, each assigned to the same first value. Thus, for example, a specific resistance value is assigned to a specific first value, for example a time value in a predetermined raw data set. Such a resistance value, ie the second value, is then arithmetically averaged and the corresponding average value is used under a predetermined time value as a basis for the reference data set. Therefore, the reference data set includes an average value assigned to this first value as described above.

  Advantageously, the number of raw data sets used to determine the reference data set is between 1 and 100, preferably between 5 and 200, particularly preferably between 10 and 100. Particularly preferred is between 15 and 40. In determining this number, on the one hand, it must be taken into account that the accuracy of the reference data set increases as the number increases. On the other hand, it should be noted that many data sets may not be processed by the user, especially during manual processing of raw data sets.

  In another advantageous embodiment, the welding apparatus is operated in a number of programs, each of which generates a reference data set. Here, the various programs are, for example, different welding programs for different types of materials, and within each welding program, a number of raw data sets are created, from which the same reference data set is generated. Is created.

  In another advantageous method, different raw data sets are partially weighted differently in determining the reference data set. For example, raw data sets that are not valid or contain outliers can be weighted differently. In particular, it is also possible to weight individual raw data sets with a factor of zero. That is, it is possible not to consider when obtaining the reference data set. It is also possible not to consider individual data values in the raw data set when determining the reference data set.

  In another advantageous way, such weighting is performed automatically. For example, outliers are identified from the raw data set, for example during differentiation or by gradient formation, and if such outliers exist, the corresponding raw data set can be completely removed from the average calculation. .

  The invention further relates to a welding apparatus. Here, the welding apparatus includes a first welding electrode, a second welding electrode cooperating with the first welding electrode, and a power feeding apparatus. Here, the power supply device supplies a current to the welding electrode. Here, at least one reference amount of the current is variable. The welding device further has a measuring device. The measuring device defines at least one electrical quantity. This amount characterizes an electrical reference amount of current supplied to the electrode. Furthermore, this welding apparatus has a control device. The control device controls the electrical reference quantity depending on the specific measurement quantity. Here, the control device controls the electrical reference quantity in consideration of a reference data set specific to the welding process to be performed. In the present invention, the PC assigned to the welding apparatus or the electronic welding apparatus has a storage device. In this storage device, at least one raw data set is stored at least temporarily. This raw data set is here specific to the welding device to be performed. Furthermore, a processor device is provided. This determines a reference data set from at least one raw data set and / or compares at least one raw data set with a reference data set.

Advantageously, the electrical reference quantity is selected from a group of reference quantities. This group includes welding current, welding voltage, output, energy, rising phase , combinations thereof, and the like, and particularly includes welding current.

  Advantageously, the processor unit determines the reference data set from a number of raw data sets or raw data set parts. A large number of raw data sets are also advantageously stored at least temporarily in the storage device. Here, each raw data set is specific to the welding process to be performed.

  In an advantageous embodiment, the measuring device is a current measuring device that measures the welding current.

  The welding device particularly preferably has a switching device. This switching device switches from the first mode in which the raw data set is read into the storage device to the second mode in which the welding process is performed taking into account the reference data set. This second mode is in particular an operating mode in which the welding process is carried out. In this case, the switching device is, for example, a mechanical switch. However, a switching device such as a software-based switch or a sensor member or a monitor member may be provided.

  The welding device preferably has a calibration mode. In this calibration mode, a reference data set is created from a number of raw data sets.

  The invention further relates to a welding apparatus. This is operated in the manner described above.

  Other advantages and embodiments will become apparent from the accompanying drawings.

The figure which shows the part of the welding equipment schematically Block diagram of a welding apparatus according to the invention Graph of many raw datasets recorded Another diagram of multiple raw datasets Flowchart of the method of the present invention

  FIG. 1 shows a schematic diagram of a welding apparatus 1. The welding apparatus 1 has a welding forceps 10. The welding forceps 10 includes two electrodes 4 and 5. These are used to weld two surfaces or two or more workpieces 3a, 3b. Here, a welding current is supplied to the welding forceps via the current lines 14 and 15. The voltage measuring lines 17, 18 or the electrode voltage cable are used for voltage measurement. The electrode voltage cables 17 and 18 are in contact with the forceps arm and are provided so as not to hinder the movement of the welding forceps 10. Nevertheless, since this cable moves with the movement of the forceps, highly flexible cables should be used for the electrode voltage cables 17, 18.

  Only one cable core or voltage measurement cable is connected to each forceps arm. The cable is thus constructed without shielding in this region. However, in another flow, the voltage cables 17 and 18 are guided along with another line, so the shield 12 is necessary at this point. Such a shield is likewise brought to ground potential, so that noise is well guided out.

  FIG. 2 shows a schematic view of the welding apparatus. Here, reference numeral 8 represents an operation surface on the PC, for example. Reference numeral 20 represents a welding forceps controller, for example, in the shape of an electrical control cabinet. Reference numeral 10 again represents welding forceps.

Reference numeral 7 relates to a measuring device for measuring the welding current I _Sch . Furthermore, the current voltage is measured by the shield 12 and another voltage measuring device (not shown), thus determining the resistance as a time dependent (as a derived quantity). Such welding resistance here consists of material resistance and contact resistance. The material resistance depends on the material and the state of the welding electrode itself as well as the two materials to be welded. Contact resistance depends on the welding process itself. In particular, it depends on the contacting surface, the resulting weld lens or weld joint and the weld electrode.

  Reference numeral 6 here represents a regulator, in particular a current-voltage regulator, and reference numeral 19 represents a transformer.

  With the configuration of the present invention, multiple welding of the program can be considered. Here, these weldings do not depend on the order in which the programs are performed. Multiple welds can be recorded simultaneously during welding control. This actually makes the creation of the reference data set very simple.

  FIG. 3 shows a diagram with a number of such raw data sets or raw characteristic curves 23a, 23b, 23c, 23d, 23e. Here, in this diagram, the resistance determined from the measured current and voltage values is shown with respect to the time of the welding process.

  It can be seen that multiple raw data sets are obtained for one welding process. These individual raw data sets are read in a recording mode in the storage device 16 (see FIG. 2). Here, on the other hand, it is possible to perform the recording as follows. In other words, it is possible to execute so that the already recorded raw data set is deleted. However, it is also possible to keep an already recorded raw data set and continue recording with another raw data set.

  Advantageously, a record of the raw data itself or a record of its progress can be viewed directly on a PC. The recording is held after the end of each recording displayed in the status display section, and the analysis mode is entered. This is used, for example, for creating a reference data set after recording all raw data.

  The entire recorded curve is shown, for example, by a suitable filter or a suitable program as shown in FIG. Now during processing, a special curve (in this case curve 23d) is selected for further processing. Here, the operator can display this curve alone. That is, the other curves 23a, 23b, 23c... Are hidden. If this curve or this raw data set 23d proves to be unsuitable for further use, for example because it represents a welding splash measurement, this data set or curve 23d is deleted. It is also possible to delete or correct individual measurement points or abnormal values from the curve 23d. This is done, for example, within the range of curve smoothing.

  It is also possible to smooth the individual curves 23d with specially matched algorithms. In this case, at this stage the splash welding curve or raw data set and other outliers should be erased. Such a raw data set is indicated in FIG. 3 by reference numerals 23c and 23e and is identified by a suddenly falling edge of the resistance course characteristic. Therefore, it is possible to automatically identify and delete such raw data sets. This is done, for example, by observing the gradient of such a raw data set.

  In a further step, the remaining curves or raw data sets are averaged, and thus a corresponding reference curve for the program or welding point is determined. This process is illustrated in FIG. Reference numeral 25 here represents an averaged curve, ie a reference curve or reference data set for this program.

  Two curves 26 and 27 located above and below the reference curve represent minimum to maximum resistance characteristics. For these resistance courses, on the one hand, it would be possible to use a curve in each full highest and lowest position. However, for each particular time value, corresponding maximum and minimum resistance values may be used. The display of the resistance course appearing at these maxima and minima is particularly useful for obtaining a measure for the scattering of the measured values. Thus, it is also possible to display the phase scatter or change in order to obtain an image of the measurement scatter process.

  The vertical line 28 shows an example selected value. That is, the time value 270 shown and the corresponding resistance value 158.

  Alternatively, the curve 25 shown here can be shown again in relation to the raw data set, or returned to the original curve state.

In a further step, a plurality of determined reference data sets are stored as reference curves in the welding control 6 (with adjustments) for this special program. In each separate operating program, the method is carried out in the same way with the determined raw data set. Furthermore, it should be noted that in this figure the calculation of the reference data set in the example of resistance measurement is shown. Correspondingly, however, measurements on the output value, energy value and rising phase value can also be determined here to produce a corresponding reference data set.

  FIG. 5 is a block diagram showing the complete method flow. In the first step, recording of the welding process is started and individual welding processes or raw data sets are stored in the control unit or the PC 8. The recording is stopped by the user's corresponding input. After a number of welding processes are recorded, individual processes or characteristic values are analyzed by the user or automatically. Here, in particular, abnormal values due to, for example, spray welding are removed. In a further step, the remaining course or characteristic values are averaged and the averaged curve obtained is stored as a reference in the welding control. Such a process is repeated for different welding programs.

  All features disclosed in this application are claimed as constituting the present invention as long as they are novel to the prior art individually or in combination.

DESCRIPTION OF SYMBOLS 1 Welding apparatus 3a, 3b Workpiece 4 Electrode 5 Electrode 6 Welding control part 7 Measuring apparatus 8 PC
DESCRIPTION OF SYMBOLS 10 Welding forceps 12 Shield 14,15 Current line 16 Memory | storage device 17,18 Voltage measurement line 19 Transformer 20 Control part 23a, b, c, d, e Raw data set or raw characteristic curve 25 Reference data Set or reference characteristic curve 26 Maximum resistance curve 27 Minimum resistance curve 28 Vertical line I _Sch welding current

Claims (19)

A method for controlling and / or monitoring a welding device (1), comprising:
Wherein the welding device (1) has at least one welding electrode (4), the welding electrode being actuated by at least one variable electrical reference quantity,
The electrical reference quantity is controlled by the control device (6),
The control of the electrical reference quantity takes into account a reference data set (25), the reference data set being in a manner that is specific to the welding process to be performed,
Determining the reference data set (25) based on at least one raw data set (23a, 23b, 23c, 23d);
The raw data set (23a, 23b, 23c, 23d) is specific to the welding process to be performed,
A method for controlling and / or monitoring a welding apparatus. A method for controlling and / or monitoring a welding device (1), comprising:
Here, the welding device (1) has at least one welding electrode (4), which is actuated by at least one electrical reference quantity,
The electrical reference quantity is controlled by the control device (6),
The control of the electrical reference quantity takes into account a reference data set (25), the reference data set being in a manner that is specific to the welding process to be performed,
The reference data set (25) is compared with at least one raw data set (23a, 23b, 23c, 23d) specific to the measurement process to be performed, and from this comparison information on the welding process to be performed is obtained. obtain,
A method for controlling and / or monitoring a welding apparatus. The electrical reference quantity is selected from a reference quantity group, which includes a welding current (I _Sch ), welding voltage, output, energy, rising phase , combinations thereof, etc., in particular welding current (I _Sch ), The method according to claim 1 or 2.   The reference data set (25) is determined from a number of raw data sets (23a, 23b, 23c, 23d), each raw data set (23a, 23b, 23c, 23d) being specific to the welding process to be performed, 4. A method as claimed in any one of claims 1 to 3.   The method according to any one of the preceding claims, wherein the reference data set (25) comprises a number of value pairs.   Method according to any one of the preceding claims, wherein the reference data set (25) is created by using mathematical operations on at least one raw data set (23a, 23b, 23c, 23d). Selecting the mathematical operation from a group of mathematical operations;
7. The method according to claim 6, wherein said group of mathematical operations comprises average value calculation, in particular arithmetic average value calculation or geometric average value calculation, integral formation, total value formation, smoothing, combinations thereof, etc. .   The method according to claim 1, wherein each of the value pairs includes a first value and at least one second value assigned to the first value.   6. The mathematical operation is used for second values of the different raw data sets (23a, 23b, 23c, 23d), each of the second values being assigned to the same first value. The method described.   The number of the raw data sets (23a, 23b, 23c, 23d) used to determine the reference data set (25) is between 1 and 1000, preferably between 5 and 200, particularly preferably 10 10. The process as claimed in claim 1, wherein the method is between ˜100, particularly preferably between 15 and 40.   11. A method according to any one of the preceding claims, wherein the welding device (1) is operable in a number of programs and creates a reference data set (25) in each program.   12. A method according to any one of the preceding claims, wherein different raw data sets (23a, 23b, 23c, 23d) are weighted differently at least partly in determining the reference data set (25).   The method of claim 9, wherein the weighting is performed automatically. A welding device (1) comprising:
The welding apparatus includes a first welding electrode (4), a second welding electrode (5) cooperating with the first welding electrode, and a current in the welding electrode (4, 5) during the welding process. _{(I Sch)} has a feeding device for supplying at least one reference amount of the current _{(I Sch)} is variable,
The welding device has a measuring device (7), which specifies at least one electrical quantity specific to the electrical reference quantity supplied to the electrode,
The welding apparatus has a control device (6), and the control device controls the electrical reference amount depending on the specific measurement amount,
The control device (6) controls the electrical reference quantity in view of a reference data set (25), the reference data set being of a type that is specific to the welding process to be performed,
The welding apparatus has a storage device (16), and at least one raw data set (23a, 23b, 23c, 23d) is stored in the storage device, and the raw data set (23a, 23b). 23c, 23d) are specific to the welding process to be performed,
The welding device has a processor device, which determines a reference data set (25) from at least one raw data set (23a, 23b, 23c, 23d).
A welding apparatus characterized by that. The electrical reference quantity is selected from a reference quantity group, and the reference quantity group includes welding current (I _Sch ), welding voltage, output, energy, rising phase , combinations thereof, etc., in particular welding current (I _Sch ). The apparatus of claim 14. The device according to claim 14 or 15, wherein the measuring device (7) is a current measuring device (7) for measuring a welding current (I _Sch ).   17. A device according to any one of claims 14 to 16, wherein the processor unit determines the raw data set (25) from a number of raw data sets (23a, 23b, 23c, 23d).   The welding device (1) has a switching device, and from the first mode in which the raw data set (23a, 23b, 23c, 23d) is read into the storage device (16) by the switching device, the reference 18. A device according to any one of claims 14 to 17, which is switched to a second mode in which the welding process is carried out taking into account the data set (25).   15. The welding device (1) has a calibration mode, in which a reference data set (25) is created from a number of raw data sets (23a, 23b, 23c, 23d). The device according to any one of 18 to 18.